But adding a constant velocity to objects does not change the fact that those which were maintaining constant velocity still maintain a constant velocity.

但是加上一个恒定速度并不会改变下述事实,即,那些正在匀速运动的物体,仍然保持匀速运动

耶鲁公开课 - 基础物理课程节选

The purpose of the exercise is to make the following precise remark.

目的是为了得到下述正确的结论

耶鲁公开课 - 基础物理课程节选